JP2011132977A - Differential gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential gear enabling a bolt assembling cost to be reduced and a low strength case to be used. <P>SOLUTION: This differential gear 11 includes a ring gear 2 rotated by a torque input from a power source, a pinion shaft 3 which is engaged with the ring gear 2 in the rotating direction and rotated when the ring gear is rotated, pinion gears 41, 42 rotatably supported on the pinion shaft 3, side gears 51, 52 meshed with the pinion gears 41, 42, and a case 6 which is rotated integrally with the ring gear 2 and the pinion gear 3 and in which the pinion gears 41, 42 and the side gears 51, 52 are stored. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a differential apparatus.

  There are differential devices used in vehicles such as automobiles. The differential apparatus, for example, uses a ring gear (11), a case (3), a pinion shaft (21), a pinion gear (19), and side gears (15, 17) to generate torque from a power source such as an engine as disclosed in Patent Document 1. It is known what communicates. The ring gear (11) is assembled to the flange (9) of the case (3) with a bolt (13), and the pinion shaft (21) is assembled to the case (3). The pinion gear (19) is rotatably supported by the pinion shaft (21), and the pinion gear (19) and the side gears (15, 17) are engaged with each other.

JP-A-6-58378

  The differential device described above transmits the torque input to the ring gear to the case by the frictional force between the ring gear and the flange generated by the axial force of the bolt. Costly, such as tightening strongly. Further, since the transmitted torque is transmitted through the case, the case also requires a strength that can withstand the transmitted torque and frictional force, and thus there is a problem that costs are increased.

  This invention is made | formed in view of the said subject, and makes it the subject which should be solved to provide the differential apparatus which can simplify the assembly | attachment of a volt | bolt and a case.

A structural feature of the invention according to claim 1 for solving the above-described problem is that a ring gear that rotates by receiving torque from a power source;
A pinion shaft that engages with the ring gear in its rotational direction and rotates integrally;
A pinion gear rotatably supported on the pinion shaft;
A side gear meshing with the pinion gear;
A case that rotates integrally with the ring gear and the pinion shaft, and that houses the pinion gear and the side gear;
It is to have.

Further, the structural feature of the invention according to claim 2 for solving the above-described problem is that a ring gear that rotates by receiving torque from a power source;
A case integrally rotatable with the ring gear;
A pinion shaft that can rotate integrally with the case, engages with the ring gear, and the torque is directly transmitted without passing through the case to rotate integrally with the ring gear;
A pinion gear housed in the case and rotatably supported by the pinion shaft;
A side gear housed in the case and meshing with the pinion gear;
It is to have.

  A structural feature of the invention according to claim 3 is that in claim 1 or 2, the invention has an engagement holding member that holds the engagement between the ring gear and the case by limiting the movement of the ring gear in the axial direction. It is.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the case includes a main body portion in which the pinion gear and the side gear are accommodated, and the main body portion. A part of the circumferential direction protrudes from the outer peripheral surface in the diameter increasing direction, and the ring gear and the case have a fastening portion fastened in the rotational direction.

  In the invention according to claim 1, since the ring gear and the pinion shaft are engaged with each other in the rotation direction and rotate integrally, the torque input to the ring gear is directly transmitted to the pinion shaft. Normally, in the differential device having such a configuration, torque input to the ring gear is transmitted to the case as a frictional force by a member that engages the ring gear and the case, and the case is rotated by the frictional force so that the torque is applied to the pinion shaft. Communicated. However, in the differential device of the present application, the case is a member for housing the pinion gear and the side gear, and rotates integrally with the ring gear and the pinion shaft, but is not a member directly involved in torque transmission. Therefore, it is only necessary to assemble so that the ring gear and the case do not come off due to the torque, and the number of members to be fastened can be reduced. Alternatively, since a large load is not applied to the case, the strength of the case itself does not have to be as high as that of the conventional case, and simplification is possible and the weight of the case can be reduced or the cost of the case can be reduced.

  In the invention according to claim 2, since the torque input to the ring gear is directly transmitted to the pinion shaft without passing through the case, the case rotates by the frictional force generated between the ring gear and the case, and the pinion shaft Does not rotate. For this reason, it is not necessary to fasten the member for fastening the ring gear and the case with high precision so that necessary torque can be transmitted, so that the assembly can be simplified. Moreover, since the case does not require strength that can withstand the frictional force that has been generated, it is possible to simplify the case, for example, by using a material that is not high strength or thinning.

  In the invention according to claim 3, since the engagement holding member is a member that holds the engagement between the ring gear and the case in the axial direction of the ring gear, the ring gear is moved by the axial force generated by the torque input to the ring gear. The engagement between the ring gear and the case is maintained.

  In the invention according to claim 4, the case is fastened to the ring gear at a fastening portion that partially protrudes in the diameter increasing direction from the outer peripheral surface of the main body portion in which the pinion gear and the side gear are accommodated. In the case where the power transmitted by the rotation of the ring gear is received as frictional force and transmitted to the pinion shaft, the ring gear is solidified by a flange portion protruding over the entire circumference. According to the differential device of the present invention, a part of the circumferential direction protrudes, and the number of fastening portions (flange portions) can be greatly reduced, so that the case can be reduced in weight.

2 is a partial cross-sectional view illustrating a configuration of a differential device 11 according to the first embodiment. FIG. It is a partial cross section figure which shows the structure of the differential apparatus 12 of this Embodiment 2. FIG. It is explanatory drawing which shows a part of differential apparatus of this modification 1. It is a partial cross section figure which shows the structure of the differential apparatus 13 of this Embodiment 3.

  A representative embodiment of the present invention will be described with reference to FIGS. The present embodiment and the modified embodiment are differential devices that transmit torque from a power source in an automobile or the like, decelerate rotation, and distribute the left and right drive shafts (first drive shaft 91 and second drive shaft 92).

(Embodiment 1)
As shown in FIG. 1, the differential device 11 according to the first embodiment includes a ring gear 2, a pinion shaft 3, pinion gears (first pinion gear 41, second pinion gear 42), and side gears (first side gear 51, second gear). Side gear 52) and case 6 are provided.

  The ring gear 2 is a helical gear that rotates about the axis A as a rotating shaft by torque from a power source and has teeth 21 formed on the outer periphery. And the inner peripheral part has the engaging part 22 which protrudes to one side of a rotating shaft direction from the tooth | gear width of the tooth | gear 21, and solidifies so that integral rotation with the pinion shaft 3 mentioned later is possible.

  The case 6 is located on the inner peripheral side of the ring gear 2 and on the inner peripheral side from the engaging portion 22, and has a main body portion 64 and a flange portion (fastening portion) 65. The main body 64 houses first and second pinion gears 42 and 42 and first and second side gears 51 and 52, which will be described later. The flange portion 65 protrudes from the outer peripheral surface 60 of the main body portion 64 in the diameter increasing direction, and engages with the engaging portion 22 in the rotation direction. The flange portion 65 is formed with a plurality of holes 61 into which pins (not shown) are inserted at equal intervals in the circumferential direction, and is engaged with the pinion shaft 3 described later by the pins. The case 6 rotates when the ring gear 2 rotates with the axis A, which is the rotation axis of the ring gear 2, as the rotation axis.

  The pinion shaft 3 is a rotating member having the axis A that is the rotating shaft of the ring gear 2 as a rotating shaft. The pinion shaft 3 is fixed to the engaging portion 22 of the ring gear 2 and is also engaged with the case 6. When torque is transmitted to the ring gear 2 and rotates, the pinion shaft 3 is directly transmitted and rotates integrally with the pinion shaft 3. The case 6 rotates as the ring gear 2 and the pinion shaft 3 rotate.

  The first and second pinion gears 41 and 42 are bevel gears whose axis of rotation is an axis B orthogonal to the axis A, and are rotatably supported on the pinion shaft 3. The first pinion gear 41 and the second pinion gear 42 are separated and accommodated in the body 64 of the case 6 with the axis A as the symmetry line. The first and second pinion gears 41 and 42 can rotate in directions opposite to each other about the axis B as a rotation axis. “Rotation” refers to rotation about the axis B as the rotation axis, and “revolution” refers to rotation due to the rotation of the pinion shaft 3 about the axis A as the rotation axis.

  The first and second side gears 51 and 52 are bevel gears that mesh with the first and second pinion gears 41 and 42 whose rotation axes are orthogonal to each other. One end of the first drive shaft 91 having the axis A as the rotation axis is in the shaft hole 51a of the first side gear 51, and one end of the second drive shaft 92 having the axis A as the rotation axis is the shaft hole 52a in the second side gear 52. Are engaged coaxially by a spline structure or the like, and can rotate together. The first and second side gears 51 and 52 are housed separately in the main body 64 of the case 6 with the axis B as the symmetry line.

  In the differential device 11 according to the first embodiment, the pinion shaft 3 is rotated when the ring gear 2 is rotated about the axis A as a rotation axis by the torque transmitted from the power source. At the same time, the case 6 rotates and the first and second pinion gears 41 and 42 revolve. When the first and second pinion gears 41 and 42 revolve, the first and second drive shafts 91 and 92 that engage with the first and second side gears 51 and 52 that engage with the first and second pinion gears 41 and 42 rotate about the axis A as the rotation axis. . Thus, the torque input to the ring gear 2 is transmitted to the pinion shaft 3, and the first and second side gears 51, 52 are rotated by the revolution of the first and second pinion gears 41, 42. 2 is transmitted to the drive shafts 91 and 92. When the first and second pinion gears 41 and 42 do not rotate, the rotation speed of the pinion shaft 3 and the rotation speed of the first and second drive shafts 91 and 92 are the same. In the process of transmitting the torque input to the ring gear 2 to the first and second drive shafts 91 and 92, when the first and second pinion gears 41 and 42 rotate in opposite directions with the axis B as the rotation axis, The first and second side gears 51 and 52 and the first and second drive shafts 91 and 92 engaged therewith rotate relative to the pinion shaft 3 in the opposite directions. That is, one of the first and second drive shafts 91 and 92 is rotated at a higher rotational speed than the pinion shaft 3, and the other is rotated at a lower rotational speed than the case 6. .

  In this way, the differential device 11 causes the first pinion gear 41 and the second pinion gear 42 to be centered when the rotational speeds of the first drive shaft 91 and the second drive shaft 92 are different, such as when the automobile turns. By rotating B in opposite directions with B as the rotation axis, it is possible to absorb the difference in rotation speed that occurs between the first drive shaft 91 and the second drive shaft 92.

  According to the differential device 11 of the first embodiment, the ring gear 2 and the pinion shaft 3 are solidified and rotate integrally, so that the torque input to the ring gear 2 is directly transmitted to the pinion shaft 3. Normally, in the differential device having such a configuration, torque input to the ring gear is transmitted to the case as a frictional force by a member that engages the ring gear and the case, and the case is rotated by the frictional force so that the torque is applied to the pinion shaft. Communicated. However, in the differential device 11, the case 6 is a member for housing the first and second pinion gears 41 and 42 and the first and second side gears 51 and 52, and is not a member directly involved in torque transmission. Therefore, the ring gear 2 and the case 6 may be assembled to such an extent that they do not come off due to torque. For example, it is not necessary to strongly fasten in consideration of the torque to be transmitted, or the number of members (bolts or the like) for fastening can be reduced, so that the assembly can be simplified and the cost can be reduced accordingly. Alternatively, since a large load is not applied to the case 6, the strength of the case itself may not be as high as that of the conventional case, and the case can be simplified. By simplifying the case, for example, the case can be made inexpensive, such as a material with low strength, or the case can be reduced in weight by reducing the thickness of the case, thereby reducing the cost of the case.

(Embodiment 2)
The differential device 12 according to the second embodiment has basically the same configuration and the same function and effect as the differential device 11 according to the first embodiment. The following description will focus on the different parts.

  The ring gear 2 has an inner peripheral portion protruding from the tooth width of the tooth 21 in one direction in the rotation axis direction, and an engagement portion 23 that is fixed to the pinion shaft 3 so as to be integrally rotatable, and a bolt (engagement holding member) 7 is inserted. Bolt holes. A plurality of bolt holes are formed at equal intervals in the circumferential direction so that the bolts 7 are inserted in the direction of the axis A at the engaging portion 23 portion.

  In the case 6, a flange portion (fastening portion) 62 is formed so that the bolt 7 is inserted at the same position as the bolt hole of the ring gear 2.

  According to the differential device 12 of the second embodiment, the engagement between the ring gear 2 and the case 6 can be held by the bolt 7, so that a shaft generated when torque is input to the ring gear 2 that is a helical gear. Since the movement of the ring gear 2 is restricted by the axial force in the direction of the center A, the engagement cannot be released. The bolt 7 can also support an axial force.

  The bolt used for engaging the conventional ring gear 7 and the case 6 has been set with a strong fastening force in order to transmit torque to the case 6. However, in the differential device 12, since the bolt 7 only needs to support the axial force generated in the ring gear 2, a strong fastening force is not required and the number of the bolts 7 can be reduced. The weight can be reduced.

(Variation 1 of Embodiment 2)
The differential device of the first modification basically has the same configuration and the same operation and effect as the differential device 12 of the second embodiment. The following description will focus on the different parts.

  As shown in FIG. 3, the case 6 used in the differential device according to the first modification has a flange portion 66 that is a part of the circumferential direction. The case 6 and the ring gear 2 are fastened by bolts 7 at four places (upper and lower sides in FIG. 3) of the upper two places and the lower two places. 3 indicates the location where the conventional flange portion 69 is present, and the broken line indicates the position of the conventional bolt 79. In the differential device according to the first modification, the flange portion can be significantly reduced, so that the case 6 can be reduced in weight. Further, since the number of bolts 7 for fastening is also reduced, the number of parts can be reduced, and the assembling cost is also reduced.

  And the structure of the flange part 66 of the case 6 used with the differential apparatus of this modification 1 can be used as the case 6 of the differential apparatus 11 of Embodiment 1 mentioned above and the differential apparatus 13 of Embodiment 3 mentioned later.

  Moreover, the flange part 69 can also be made into the shape which protrudes in not only two circumferential directions but three, four, and a diameter expanding direction.

(Embodiment 3)
The differential device 13 according to the third embodiment has basically the same configuration and the same function and effect as the differential device 11 according to the first embodiment. The following description will focus on the different parts.

  As shown in FIG. 4, the ring gear 2 has an inner peripheral portion protruding from the tooth width of the tooth 21 in one direction in the rotation axis direction, and an engagement portion 24 that is fixed to the pinion shaft 3 so as to be integrally rotatable. And a ring gear spline portion 25.

  In the case 6, a flange portion (fastening portion) 63 that is spline-engaged with the ring gear spline portion 25 is formed on an outer surface portion facing the inner peripheral side of the ring gear 2.

  In the axial direction of the shaft center A, a snap ring (engagement preventing member) 8 is disposed on one end side of the engaging portion 24 and the flange portion 63 so as to sandwich the outer shape of the case 6. The snap ring 8 prevents the ring gear 2 and the case 6 from being disengaged by the ring gear 2 moving in the direction of the axis A due to the axial force generated when torque is input to the ring gear 2. It is installed at a position opposite to the axial force.

  According to the differential device 13 of the third embodiment, since the engagement between the ring gear 2 and the case 6 can be held by the snap ring 8, it is generated when torque is input to the ring gear 2 that is a helical gear. Disengagement can be prevented by the axial force in the direction of the axis A. The snap ring 8 can also support an axial force.

  The bolt used to engage the conventional ring gear 2 and the case 6 has been set with a strong fastening force in order to transmit the torque to the case 6 as a frictional force. However, in the differential device 13, since the torque input to the ring gear 2 is transmitted to the pinion shaft 3 without passing through the case 6, it is not necessary to strongly fasten the ring gear 2 and the case 6 with bolts. Therefore, since the number of bolts can be reduced and there is no need to strongly tighten the bolts, the assembling cost related to the reduction in the number of components and strong fastening can be reduced.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the ring gear 2, the engaging portions 22, 23, and 24 protrude in the axial direction, but the outer peripheral teeth 21 are also extended in the axial direction by a length necessary to engage with the pinion shaft 3. Different shapes may be used.

11, 12, 13: differential device, 2: ring gear,
21: Teeth, 22, 23, 24: Engagement part,
25: Ring gear spline part, 3: Pinion shaft,
41: First pinion gear, 42: Second pinion gear,
51: 1st side gear, 51a, 52a: Shaft hole,
52: Second side gear, 6: Case,
60: outer peripheral surface, 61: hole,
62, 63, 65, 66: flange part (fastening part),
64: body part, 63: case spline part,
69: Conventional flange portion, 7: Bolt (engagement holding member),
79: Conventional bolt, 8: Snap ring (engagement holding member),
91: first drive shaft, 92: second drive shaft.

Claims (4)

A ring gear that rotates by receiving torque from a power source;
A pinion shaft that engages with the ring gear in its rotational direction and rotates integrally;
A pinion gear rotatably supported on the pinion shaft;
A side gear meshing with the pinion gear;
A case that rotates integrally with the ring gear and the pinion shaft, and that houses the pinion gear and the side gear;
A differential apparatus comprising: A ring gear that rotates by receiving torque from a power source;
A case integrally rotatable with the ring gear;
A pinion shaft that can rotate integrally with the case, engages with the ring gear, and the torque is directly transmitted without passing through the case to rotate integrally with the ring gear;
A pinion gear housed in the case and rotatably supported by the pinion shaft;
A side gear housed in the case and meshing with the pinion gear;
A differential apparatus comprising:   The differential device according to claim 1, further comprising an engagement holding member that holds the engagement between the ring gear and the case by restricting movement of the ring gear in an axial direction thereof.   The case includes a main body portion in which the pinion gear and the side gear are accommodated, a part of a circumferential direction protrudes from the outer peripheral surface of the main body portion in a diameter increasing direction, and the ring gear and the case are fastened in a rotation direction. The differential device according to any one of claims 1 to 3, further comprising a fastening portion.

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